Light-valves are implemented in a wide variety of display technologies. For example, display panels are gaining in popularity in many applications such as televisions, computer monitors, point of sale displays, personal digital assistants and electronic cinema to mention only a few applications.
Many light valves are based on liquid crystal (LC) technologies. Some of the LC technologies are prefaced on transmittance of the light through the LC device (panel), while others are prefaced on the light traversing the panel twice, after being reflected at a far surface of the panel.
The LC material is used to selectively rotate the axes of the liquid crystal molecules. As is well known, by application of a voltage across the LC panel, the direction of the LC molecules can be controlled and the state of polarization of the reflected light selectively changed. As such, by selective switching of the transistors in the array, the LC medium can be used to modulate the light with image information. This modulation may be used to provide dark-state light at certain picture elements (pixels) and bright-state light at others, where the polarization state governs the state of the light. Thereby, an image is created on a screen by the selective polarization transformation by the LC panel and optics to form the image or ‘picture.’
In many LCD systems, the light from a source is selectively polarized in a particular orientation prior to being incident on the LC layer. The LC layer may have a voltage selectively applied to orient the molecules of the material in a certain manner. The polarization of the light that is incident on the LC layer is then selectively altered upon traversing through the LC layer. Light in one linear polarization state is transmitted by a polarizer (often referred to as an analyzer) as the bright state light; while light of an orthogonal polarization state is reflected or absorbed by the analyzer as the dark-state light.
While LCD devices are becoming ubiquitous in display and microdisplay applications, there are certain drawbacks associated with known devices, their components and methods of manufacture. For example, in known structures the efficiency of light transmission to the final imaging surface is rather poor, and results in poor image quality.
What is needed therefore is a method and apparatus that overcomes at least the shortcomings of the known devices described above.